Step 1: Three years have passed since the start of the Clone Wars and neither side seems to be gaining much ground any longer. Chancellor Palpatine has been able to use the Clone Wars to extend his term of office, but has now apparently reached the limits to where he can stretch his emergency powers. So he devises a bold move, by allowing himself to be kidnapped by Count Dooku, until Anakin and Obi-Wan rescue him. As Anakin emerges victoriously and Count Dooku has out-lived his usefulness, Palpatine convinces Anakin to kill Dooku. According to the novelization, Palpatine's original plan was for Dooku to kill Kenobi, enabling Palpatine to recruit Anakin immediately after Dooku's death. Kenobi's survival prompted Palpatine to alter his plans slightly.
Step 2: After his rescue, which likely garnered much more sympathy for Palpatine as well as renewing the fear for Separatist aggression, the Senate grants him even more emergency powers. Palpatine receives near-complete control over the Republic for the rest of the war, the Senate fulfilling merely an advisory function.
Step 3: Palpatine announces the appointment of planetary governors to every system of the Republic, further bypassing any influence from the Senate (Revenge of the Sith deleted scene).
Step 4: Palpatine, under the guise of Darth Sidious, orders General Grievous to move all the Separatist leaders to the planet Mustafar stating that the end of the war is near.
Step 5: Palpatine then gives the news to Anakin as to where Grievous is hiding. So the Jedi send Obi-Wan to Utapau to capture and/or kill Grievous with a battalion of Clone troops.
Step 6: After Obi-Wan engages Grievous, Mace Windu orders Anakin to deliver the news to Palpatine as the Jedi were suspicious of Palpatine as of late. During the conversation between Anakin and Palpatine, Palpatine admits (more or less) that he is the Sith Lord and tries to convince Anakin that he can save Padme from dying in child birth if Anakin joins the dark side.
Step 7: Anakin returns to Mace Windu and informs him that Chancellor Palpatine is the Sith Lord. Windu and three other Jedi Masters go to the Chancellor's office to arrest him. Prediciting that Anakin would report him to the Jedi, Palpatine engages the Jedi in lightsaber combat, and easily kills the other three in mere seconds. However, Palpatine is defeated by Windu (though likely that he threw the fight when sensing Anakin approaching). At that moment, Anakin enters and Palpatine appeals to him by cowering and begging for his life, calling the Jedi traitors, and begging for Anakin's help. Anakin pleads with Windu that official legal procedures should be followed, desperately (and unsuccessfully) attempting to hide his true motivation of needing Palpatine alive. When Windu decides Palpatine is too dangerous to be kept alive, as he has control over the entire senate and courts, he moves to kill Palpatine; Anakin disarms Windu, literally, allowing Palpatine to strike the finishing blow. Anakin is devastated in the knowledge that he intentionally assisted with the killing of a fellow Jedi, but Palpatine insists that Anakin merely intervened in a traitor's plot. Willing to believe this, Anakin feels he now has no choice but to become Palpatine's new apprentice, even more so to gain Palpatine's help in saving Padme's life. Palpatine then pronounces Anakin will now be known as Darth Vader, and tells him they will work together to discover the secret of cheating death and living forever.
Step 8: Palpatine sends Vader to the Jedi Temple with a garrison of clone troops to end the Jedi "conspiracy" and kill every Jedi. He then orders him to go to Mustafar to kill Nute Gunray and the other Separatist Leaders afterwards.
Step 9: Palpatine sends orders to the Clone Commanders around the galaxy to "Execute Order 66." which was a top secret order (apparently implanted into the Clone's minds) to immediately execute every single Jedi with extreme prejudice. Being more or less living droids, the Clones do so without question.
Step 10: Palpatine orders Nute Gunray to shut down all droid units immediately, thus ending the Clone Wars. Gunray and the rest of the Trade Federation and Separatist leaders are then slaughtered by Vader.
Step 11: Palpatine calls an emergency session in the Galactic Senate and elaborates on the "assassination plot" by the Jedi that left him disfigured. He then announces his intention to turn the Republic into the first Galactic Empire, for a safe and secure society. Out of sympathy for his suffering and sacrifice, the Senate enthusiastically gives him their mandate, thus making him Emperor of the Galaxy for life and the Empire effectively a dictatorship. The Galactic Senate then becomes known as the Imperial Senate (as mentioned in Star Wars: Episode IV), though has diminished power by that point.
Step 12: Perhaps forseeing that the Imperial Senate will one day object to his tyranny, Palpatine commissions the construction of the Death Star as a way to extort the systems into submission.
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